Aspects of the present invention relate to an elastic coupling device or piece for elastically connecting a damping mass like a gas generator to a motor vehicle part exposed to oscillations and/or vibrations, in particular an airbag module, a steering wheel structure or a body part fixed to the steering wheel structure.
During driving of a motor vehicle highly dynamic vibrations and/or oscillations act upon the vehicle body and thus also upon the steering wheel that is to be operated by the driver of the motor vehicle. It is common knowledge to dampen these vibrations and oscillations by elastically and oscillatingly suspending in the range of the natural frequency of the steering wheel a damping mass for example at the steering wheel. In the area of the steering wheel the damping mass is often formed by the gas generator of an airbag module that is to be fixed to the steering wheel of the motor vehicle.
An important aspect of the damping is determined by the design of the elastic connection system that is defined by the elastic coupling piece. From DE 10 2004 051 942 B4 an elastic coupling piece is known that comprises a support element fixed towards the vehicle body, for example to the steering wheel structure, rigidly via screw connections. The support element consists of a plastic material like PA66 with a proportion of fibre glass of 30 to 40%. DE 10 2004 051 942 B4 teaches to arrange a solid spring body made of elastomer material between the gas generator and the motor vehicle body such that a damping counter-oscillation is possible. Openings are provided in the support element that are lined and overmoulded with elastomer material in order to realise a force-transmitting positive connection between the support element and the spring body. In this way a structural fixation is created between the support element and the spring body with which even large loading tensions can safely be transmitted from the support element into the spring body and back. A structural engagement of the spring body with the support element and vice versa is realised by the lining of the openings. This fixation based on a positive connection proved to be sufficiently firm but requires a larger space due to the openings or anchor holes and creates challenges concerning manufacturing leading to an increased financial burden for the manufacturer.
However, for the known overmoulding of the support element no bonding agent is required for the elastomer material for forming undercuts and engagement structures in order to provide a force-transmitting transition between the elastomer material and the plastic material of the support element.